JP3260901B2 - Electron multiplier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron multiplier for multiplying an incident electron flow by multi-layered dynodes.

[0002]

2. Description of the Related Art A conventional electron multiplier and its detailed structure are shown in FIGS. This electron multiplier constitutes a photomultiplier having a photocathode 106 on the lower surface of an entrance window 101, and a dynode 1 is placed in a bottomed cylindrical vacuum vessel 105.
The electron multiplier 107, the anode 103, and the cathode 104, in each of which a plurality of layers 02 are stacked, are provided. Each dynode 102 has a disk-shaped ceramic spacer 10 therebetween.
8 are interposed at predetermined intervals.
By interposing the ceramic spacer 108 between the dynodes, columnar ceramic spacer groups 109 are formed at four locations around the dynode. Twelve stem pins 110 connected to the external power supply terminal are arranged at equal intervals in a ring shape.

Each dynode 102 has fixing holes 114 at four locations around the dynode 102, and has flat connection terminals 115 protruding in the radial direction.
And the corresponding stem pin 110 are electrically connected by the wiring member 112.

[0004]

As described above, the structure of the conventional electron multiplier tube includes the connection terminal 115 and the stem pin 110.
The connection between them is made by using the wiring member 112 which is not formed in consideration of the positional relationship with the wiring member 112 and whose length and shape can be freely changed. Therefore, it is necessary to process the wiring member 112 three-dimensionally according to the connection site.

Further, since the connection terminal 115 has a flat plate shape as shown in the figure, when the wiring member 112 is connected,
It was necessary to bend the end of this wiring member along the connection terminal 115.

Further, by using the wiring member as described above, one end of the wiring member 112 is connected to the stem pin 110.
In addition, it is necessary to resistance-weld the other end to the connection terminal 115, respectively, which is one factor that reduces the efficiency of the assembling work. This drawback becomes more conspicuous as the electron multiplier manufactured becomes smaller, and this welding operation requires skill and has a problem that the assembling work efficiency is further reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide an electron multiplier that can be easily manufactured even when the electron multiplier is downsized. Is to do.

[0008]

Accordingly, an electron multiplier according to the present invention is provided with a plurality of dynodes which are stacked in a plurality of stages and constitute an electron multiplier for multiplying an incident electron flow. And a plurality of connection pins extending along the stacking direction of the dynodes for applying a predetermined voltage. At the outer peripheral portion of each dynode, an engagement member that engages with the connection pin is protruded at a position facing the corresponding connection pin, and the engagement member of the dynode at each stage is connected to each connection pin. It is composed.

The engaging member may be provided with a pair of guide pieces, and may be configured to guide a connection pin between the pair of guide pieces.

It is preferable that the connection pins are arranged annularly around the stacked dynodes, and the engaging members of each dynode are formed at positions corresponding to the corresponding connection pins.

Further, the connection pin may be formed of a metal material having a lower rigidity in the vicinity of the end connected to the engagement member than other portions of the connection pin.

Further, the electron multiplier having such a structure can be applied to a photomultiplier further provided with a photocathode.

[0013]

Each dynode is provided with an engaging member in advance corresponding to the position of the corresponding connection pin. Therefore, when assembling, the positional relationship between the engaging member of each dynode and each connection pin is in agreement, and in this portion, the guide member and the connection pin may be connected by welding or the like.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1A, 1B and 2 show a photomultiplier tube according to this embodiment. In this photomultiplier tube, a vacuum vessel is formed by a circular light receiving surface plate 1 for receiving incident light, a cylindrical metal side tube 3 provided on an outer peripheral portion thereof, and a circular stem 4 constituting a base portion. Inside this, an electron multiplier 5 for multiplying the incident electron flow is provided.

A photocathode 2 is provided on the lower surface of the light receiving face plate 1,
A focusing electrode 6 is provided between the photocathode 2 and the electron multiplier 5. Accordingly, each electron emitted from the photocathode 6 has its trajectory converged by the influence of the focusing electrode 6, and
The light enters a predetermined area of the electron multiplier 5.

The electron multiplier 5 is formed by stacking a plurality of dynodes 7 formed in the shape of a square plate in a plurality of stages, and each stage has a large number of electron multiplier holes 8 in a matrix. Are arranged and formed. Below the stacked dynodes 7, a dynode 9 and a dynode 10 at the last stage are sequentially arranged.

As shown in FIG. 3 on an enlarged scale, U-shaped connection terminals 20 for connecting to stem pins 11 described later are integrally formed on the outer peripheral portions of the dynodes 7, 9, and 10, respectively. ing. The connection terminal 20 has a pair of guiding guide pieces 20a protruding forward, and a central concave portion 20a.
b has a diameter substantially the same as the diameter of the stem pin 11, and has a structure in which the connection terminal 20 and the stem pin 11 are fitted by pushing the stem pin 11 into the recess 20 b.

Each of the dynodes 7, 9, and 10 is provided with a connection terminal 20 at a position facing a predetermined stem pin 11, and as shown in FIG. Three positions are provided along each side of the dynode corresponding to the positions.

A total of twelve stem pins 11 are connected to an external voltage terminal and apply a predetermined voltage to each of the dynodes 7, 9, 10 and the like through the stem 4 serving as a base. Three stem pins 11 are arranged along each side so as to surround the dynodes stacked in a cubic shape, and are fixed to the stem 4 by tapered hermetic glass 12. In addition, each stem pin 11
In the example of FIG. 1A, the top end of the dynode 7 and the corresponding four stem pins 11 are connected to the corresponding connection terminal 20. FIG. The material of the stem pin 11 is formed of a relatively soft material such as copper near the portion corresponding to the connection terminal 20, and the other portion is formed of a relatively hard material such as stainless steel. As a result, the stem pin 11 is firmly fixed to the stem 4, and at the time of fitting the stem pin 11 to the connection terminal 20, it is possible to avoid applying extra stress to the stem 4. In addition, the tip of the stem pin 11 is slightly inclined inward to fit the connection terminal 20, but this operation can be easily performed. In addition, even if the stem pin 11 is integrally formed with the same material, it can be applied sufficiently.

As shown in FIG. 2, a metal tip tube 13 whose end is crimped and sealed is projected from the center of the bottom of the stem 4. Through this metal tip tube 13,
An alkali metal is introduced into the inside of the vacuum vessel, or the remaining gas is evacuated, and thereafter, sealing is performed as shown in the figure.

When assembling a photomultiplier using such dynodes 7, 9, and 10, the connection terminals of the dynodes 7, 9, and 10 are assembled with the dynodes 7, 9, and 10 assembled. 20 and corresponding stem pin 1
Since the positions coincide with each other, they need only be directly connected to each other by resistance welding or the like, and this connection step can be performed extremely easily. Further, since the connection terminal 20 is formed in a U-shape with one end open, instead of a conventional flat plate shape, the stem pin 11 is securely fitted inside the connection terminal 20, and the tip of the stem pin 11 is bent as in the conventional case. Need not be applied. After the stem pin 11 is fitted into the concave portion 20b of the connection terminal 20, the distal ends of the guide pieces 20a on both sides thereof are pressed against each other, so that the stem pin 11 is held inside the connection terminal 20. You can also. Thus, the subsequent welding operation can be easily performed.

In this embodiment, an example is shown in which the connection terminal 20 is formed in a U-shape. However, the present invention is not limited to this shape. For example, in addition to the shape shown in FIG. Any shape, such as a mold, a U-shape, or a C-shape, may be used as long as the stem pin 11 can be received and engaged inside thereof.

In this embodiment, an example is shown in which the recess 20b of the connection terminal 20 and the stem pin 11 are fitted.
It is not always necessary to accommodate the connection terminals in the fitted state.
It suffices if the stem pin 11 can be positioned inside the inside.

Further, the connection terminal 20 exemplified in this embodiment
Although the example in which the dynode provided with is provided in the photomultiplier tube provided with the photocathode has been described, it is needless to say that the dynode can be provided in the electron multiplier tube.

[0026]

As described above, the electron multiplier according to the present invention has a plurality of connection pins extending along the direction in which the dynodes are stacked, and the outer periphery of each dynode faces the connection pins. At the position, an engaging member that engages with the connection pin is protruded.

Therefore, since the positional relationship between the connecting pin and the engaging member to be connected to each other coincides with each other, it is not necessary to use a wiring member for the connection as in the conventional case, and it is also necessary to bend the connecting pin. Since there is no such connection, it is possible to easily carry out this connection work. In addition, since the resistance welding may be performed at only one position of the engagement portion with the engagement member, the working efficiency of the assembly can be improved.
In addition, these effects are more remarkably exhibited when a small electron multiplier is manufactured as compared with the related art.

[Brief description of the drawings]

FIG. 1A is a side view showing a photomultiplier tube according to the present invention, in which a metal side tube is broken to show an internal structure thereof;
(B) is a top view of the electron multiplier.

FIG. 2 is a bottom view of the photomultiplier tube of FIG.

FIG. 3 is an enlarged perspective view showing a connection terminal provided on a dynode.

FIG. 4 is a perspective view showing another embodiment of the connection terminal.

FIG. 5 is a side view showing a conventional electron multiplier.

FIG. 6 is a top view of the electron multiplier of FIG. 5;

FIG. 7 is a bottom view of the electron multiplier of FIG. 5;

FIG. 8 is a plan view showing a dynode provided in the electron multiplier of FIG. 5;

[Explanation of symbols]

5: electron multiplier, 7, 9, 10, dynode, 11: stem pin (connection pin), 20: connection terminal (engaging member),
20a: Guide piece (a pair of guide pieces).

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01J 43/00-43/30

Claims (5)

(57) [Claims] 1. A plurality of dynodes that are stacked in a plurality of stages and constitute an electron multiplying unit that multiplies an incident electron flow, and a predetermined voltage is applied to each of the dynodes along a stacking direction of the dynodes. A plurality of connecting pins extending therefrom, and an outer peripheral portion of each of the dynodes is provided with an engaging member projecting at a position facing the corresponding connecting pin to engage with the connecting pin. An electron multiplier formed by connecting the joining member and each of the connection pins. 2. The electron multiplier according to claim 1, wherein the engagement member includes a pair of guide pieces, and guides the connection pin between the pair of guide pieces. 3. The connection pins are arranged annularly along the periphery of the stacked dynodes, and each of the dynodes is provided with a corresponding one of the engaging members at a position facing the corresponding connection pin. The electron multiplier according to claim 1 or 2, wherein is formed. 4. The electron multiplying device according to claim 3, wherein the connection pin is formed in the vicinity of an end connected to the engagement member with a metal material having lower rigidity than other portions. tube. 5. The electron multiplier according to claim 1, wherein the electron multiplier is a photomultiplier provided with a photocathode.